Explainer: High blood pressure stresses the heart and blood vessels

adolescent: Someone in that transitional stage of physical and psychological development that begins at the onset of puberty, typically between the ages of 11 and 13, and ends with adulthood.

artery: Part of the body’s circulation system. There are several. Each is a major tube running between the heart and blood vessels that will move blood to all parts of the body.

blood pressure: The force exerted against vessel walls by blood moving through the body. Usually this pressure refers to blood moving specifically through the body’s arteries. That pressure allows blood to circulate to our heads and keeps the fluid moving so that it can deliver oxygen to all tissues. Blood pressure can vary based on physical activity and the body’s position. High blood pressure can put someone at risk for heart attacks or stroke. Low blood pressure may leave people dizzy, or faint, as the pressure becomes too low to supply enough blood to the brain.

cell: (in biology) The smallest structural and functional unit of an organism. Typically too small to see with the unaided eye, it consists of a watery fluid surrounded by a membrane or wall.

compound: (often used as a synonym for chemical) A compound is a substance formed when two or more chemical elements unite (bond) in fixed proportions. For example, water is a compound made of two hydrogen atoms bonded to one oxygen atom. Its chemical symbol is H₂O.

diastolic: An adjective that describes the period of muscle relaxation in the heart’s blood-pumping cycle. It’s when the chambers of the heart fill up with blood and the circulatory system’s blood pressure is at its lowest level. This is referred to as the body’s diastolic blood pressure.

force: Some outside influence that can change the motion of an object, hold objects close to one another, or produce motion or stress in a stationary object.

gauge: A device to measure the size or volume of something. For instance, tide gauges track the ever-changing height of coastal water levels throughout the day. Or any system or event that can be used to estimate the size or magnitude of something else. (v. to gauge) The act of measuring or estimating the size of something.

glucose: A simple sugar that is an important energy source in living organisms. As an energy source moving through the bloodstream, it is known as “blood sugar.” It is half of the molecule that makes up table sugar (also known as sucrose).

heart attack: Permanent damage to the heart muscle that occurs when one or more regions of it become starved of oxygen, usually due to a temporary blockage in blood flow.

high blood pressure: The common term for a medical condition known as hypertension. It puts a strain on blood vessels and the heart.

hypertension: The medical term for high blood pressure. It can put a strain on blood vessels and the heart.

impair: (n. impairment) To damage or weaken in some way.

kidney: Each in a pair of organs in mammals that filters blood and produces urine.

mercury: Sometimes called quicksilver, mercury is an element with the atomic number 80. At room temperature, this silvery metal is a liquid. Mercury is also very toxic.

muscle: A type of tissue used to produce movement by contracting its cells, known as muscle fibers. Muscle is rich in protein, which is why predatory species seek prey containing lots of this tissue.

oxygen: A gas that makes up about 21 percent of Earth’s atmosphere. All animals and many microorganisms need oxygen to fuel their growth (and metabolism).

pressure: Force applied uniformly over a surface, measured as force per unit of area.

ratio: The relationship between two numbers or amounts. When written out, the numbers usually are separated by a colon, such as a 50:50. That would mean that for every 50 units of one thing (on the left) there would also be 50 units of another thing (represented by the number on the right).

stress: Pressure or tension exerted on some object.

stroke: (in biology and medicine) A condition where blood stops flowing to part of the brain or leaks in the brain.

systolic: An adjective that describes the period of muscle contraction in the heart’s blood-pumping cycle. It’s when the chambers of the heart known as the ventricles squeeze tight, forcing the blood that had been in them to eject through the aorta and into the circulatory system. This blood will move toward the lungs (where it will pick up a new influx of oxygen). At this time, the circulatory system’s blood pressure is at its highest level. This is referred to as the body’s systolic blood pressure.

toddlers: Children between 9-months and 2-years old. The term refers to the fact that these youngsters only recently learned to walk and are not yet totally steady on their feet.

unit: (in measurements) A unit of measurement is a standard way of expressing a physical quantity. Units of measure provide context for what numerical values represent and so convey the magnitude of physical properties. Examples include inches, kilograms, ohms, gauss, decibels, kelvins and nanoseconds.

vein: (in zoology) Part of a body’s circulation system. These tubes usually carry blood toward the heart.